Grill, broil, or toast bread. Arrange toasts on a platter or individual plates.
Using a very sharp or serrated knife, cut tomatoes into paper thin slices. Discard core and end pieces.
Arrange tomato slices from 1 tomato across surface of each toast, overlapping if necessary. Using a spatula, press tomato slices into toast to release juices into bread. Drizzle with oil and sprinkle with salt.
Mix olives, parsley, capers, and thyme in a small bowl. Divide mixture among toasts, spooning over tomatoes, and serve.